By Ben Patterson
11/09/2006
URL: http://asia.cnet.com/digitalliving/tips/0,3800004921,39242481,00.htm

	Cellular technology: a brief history See how it all started for cell phones
	Types of 3G Not all high-speed technologies are the same
	Handsets with 3G Show me the 3G-enabled phones out there
	3G glossary Decipher 3G's alphabet soup

Cellular technology: A brief history

Remember those telltale twisty antennas on the roofs of cars in the 1980s? Those cool customers on their car phones were using Advanced Mobile Phone Service, or AMPS. This first-generation analog network may have been cutting edge at the time, but it soon became notorious for its iffy call quality. Even worse, anyone with a police radio scanner can easily eavesdrop on AMPS calls, which travel through the air without any scrambling or encryption. AMPS still is available today on handsets from some phone vendors, but it is largely fading as a technology.


The 1990s marked the arrival of two digital networks: CDMA, popular in the United States and a few other countries; and GSM, the dominant technology overseas. These second-generation (2G) networks spread voice calls across several wireless spectrums, making for more reliable connections that are much harder--though not impossible--for hackers to intercept. More importantly, CDMA and GSM networks are also capable of sending a sliver of data along with voice signals, making possible for such features as text messaging (SMS), caller ID, and conference calling.

Though the move to 2G was a great leap in terms of the technology, the splintering of the CDMA and GSM camps created a mess in some countries such as the US which had some carriers opting for GSM while others choosing CDMA. While each camp claims to have the advantage, the schism resulted in two competing networks with little incentive to create a unifying 3G standard. Conversely in Europe, 3G arrived much more quickly because all carriers were working off a government-mandated standard.

Of course, there were other factors working against 3G's adoption in some countries. Rolling out the new networks was very expensive, and customers had to be sold on the services. Furthermore, the move also involved technological constraints. Carriers had to bridge the gap between slow-as-molasses 2G service and zippy 3G with "2.5G" network enhancements. In operation a couple years now, 2.5G networks let you download ring tones, listen to short audio clips, send multimedia messages (MMS), or surf the Web, albeit slowly. These services include GPRS, which is capable of transmitting and receiving data at an average of about 30Kbps to 40Kbps, or a little slower than standard 56K dial-up service and EDGE, another GSM enhancement that manages about 90Kbps on an average day, or almost twice as fast as dial-up. On the CDMA side is 1xRTT, an early version of CDMA2000, which squeaks in about 60Kbps to 80Kbps. The next step, of course, is 3G and beyond. But some important differences remain.

Types of 3G

There are two main flavors of 3G: UMTS (Universal Mobile Telephone Service), which is being rolled out over existing GSM networks, and CDMA2000, which brings 3G speeds to CDMA networks; for a detailed explanation of terms, see the glossary. Both UMTS and CDMA2000--which has two high-speed offshoots, the data-only 1xEV-DO and the voice-plus-data 1xEV-DV--are already available in major cities with more expansion set for 2006. Speeds for both should be about DSL quality. We're also beginning to see discussions of 3.5G and 4G technologies such as HSDPA and WiMax, which should provide cable modem and gigabyte Ethernet speeds.

Of course, you'll need a 3G-capable phone to use one of the new high-speed networks. After a slow start, a wide assortment of 3G handsets is now available from the carriers. All the mobiles offer support for the new 3G networks, and they come in a variety of styles, from stylish and trendy--such as the Samsung SGH-Z540--to simple and functional, as in the Nokia 6233. For a complete list of phones, see the next page for all new 3G cell phone reviews. Laptop users also can take advantage of 3G networks for on-the-go broadband without a Wi-Fi network; all you need is a carrier-supplied PC Card.

Services and speeds 

	1G	2G	2.5G
Technology	AMPS	GSM CDMA iDen	GPRS 1xRTT EDGE
Speeds	n/a	Less than 20Kbps	30Kbps to 90Kbps
Features	Analog (voice only)	Voice; SMS; conference calls; caller ID; push to talk	MMS; images; Web browsing; short audio/video clips; games, applications, and ring tone downloads

	3G	3.5G	4G and beyond
Technology	UMTS 1xEV-DO	HSDPA (upgrade for UMTS) 1xEV-DV	WiMax*
Speeds	144Kbps to 2Mbps	384Kbps to 14.4Mbps	100Mbps to 1Gbps
Features	Full-motion video; streaming music; 3D gaming; faster Web browsing	On-demand video; videoconferencing	High-quality streaming video; high-quality videoconferencing; Voice-over-IP telephony

3G glossary
Confused by all the technical jargon and acronyms surrounding 3G? We can't blame you. Here's a quick guide to the terms you'll need to know.

1xEV-DO: Also known as Evolution, Data-Only, this subset of CDMA2000 runs on CDMA networks and reaches peak speeds of 2.4Mbps and averages 300Kbps to 600Kbps. As its name implies, EV-DO networks handle only high-speed data; handsets supporting EV-DO would use the underlying CDMA network for voice calls.

1xEV-DV: Also known as Evolution, Data-Voice, 1xEV-DV is the next step in CDMA2000 technology after 1xEV-DO, handling both data and voice calls at speeds up to 2.4Mbps.

1xRTT: A subset of CDMA2000 that runs on CDMA networks, 1xRTT (or Radio Transmission Technology) offers speeds of up to 144Kbps, although users will typically get speeds between 60Kbps and 80Kbps. While 1XRTT is sometimes referred to as 3G technology, it falls a bit short in terms of speed and actually is 2.5G.

AMPS: Advanced Mobile Phone Service, the first-generation, analog cellular network that arrived in the 1980s. While digital networks have taken over most populated areas, AMPS still covers rural areas in some countries (eg the US) that CDMA and GSM can't reach.

CDMA: Code-Division Multiple Access, a 2G digital cellular network first launched in 1995 and--until a recent surge by 2G competitor GSM--the unchallenged leader in stateside cell service.

CDMA2000: The next step in CDMA technology, CDMA2000 comprises 1xRTT (2.5G), 1xEV-DO, and 1xEV-DV (both 3G).

EDGE: Enhanced Data rates for GSM Evolution (or Enhanced Data GSM Environment), a 2.5G enhancement for GSM with a theoretical top speed of 384Kbps, although real-world speeds will be closer to 90Kbps.

GPRS: An upgrade for GSM networks, General Packet Radio Service is a 2.5G technology that bumps data speeds up to 50Kbps, although real-world speeds are closer to 30Kbps and 40Kbps.

GSM: Global System for Mobile Communications. This 2G (about 9.6Kbps) digital network is most pervasive in international markets.

HSDPA: An enhancement for 3G UMTS networks, High Speed Downlink Packet Access promises bone-rattling speeds of up to 14.4Mbps, compared to a "mere" top speed of 2Mbps for UMTS.

iDEN: A 2G network primarily used for business. Nextel was the first cellular network with PTT functionality but it now is offered by others.

PTT: Push to talk, a two-way mobile technology that works like a walkie-talkie and is not the same as placing a normal voice call.

TDMA: Time Division Multiple Access, the original digital technology on which GSM is based.

UMTS: Universal Mobile Telephone Service, the 3G service that GSM carriers Cingular and T-Mobile plan to roll out for its subscribers. UMTS boasts speeds of up to 2Mbps, although users will typically see speeds in the 300Kbps-to-400Kbps range.

WiMax: A high-performance version of Wi-Fi, WiMax (or 802.16) networks would offer the bandwidth of Wi-Fi at ranges measured in miles rather than feet. Many industry observers feel that WiMax could be the cornerstone of 4G wireless networks, boasting speeds rivaling those of wired gigabit Ethernet networks.